Wastewater, such as from food and beverage processing, transportation processing or steel mill processing, often contains suspended matter, which must be removed to provide suitable water for use in domestic and industrial applications. Raw influent water, such as from lakes, streams and rivers can also contain suspended material. The suspended matter may contain large solids that are easily removed by settling, and other suspended materials that are not easily removed by settling, such as dispersed colloids or colloidal oils. Suspended materials are typically removed by clarification, which includes the steps of coagulation, flocculation and sedimentation.
Additives containing chitosan have been used to enhance clarification, but the effectiveness was limited, as chitosan has low water solubility and low cationic charge. Larger amounts of chitosan in the additive cause the additives to become insoluble in the aqueous media.
It is desirable to improve clarification methods for removing suspended material by providing improved and environmentally-friendly additives and methods.